Health effects from exposure to organophosphate pesticides in workers and residents in Israel

Major findings from our work on exposures and effects from organophosphate-containing pesticides in selected occupational and community patients and groups in Israel are reviewed as a basis for recommending control measures. The worker groups were pilots, ground-crews, and field workers; exposed nonworkers were adults and children living in kibbutzim with drift exposures, and household residents in houses treated by pest exterminators. In all groups, evidence of exposure-illness associations was found even though persons with acute poisoning were not seen. Complaints (headache, dizziness, fatigue, nausea, breathing problems, abdominal cramps, and tingling in extremities) were associated with within-normal depressions in cholinesterase activity. Whole blood and plasma cholinesterase activity were slightly more sensitive indicators of mixed exposure than red blood cell cholinesterase activity. High alkyl phosphate levels and symptoms were seen in individuals with within-normal limit depressions in cholinesterase activity. Complaints of weakness and tingling in hands and feet, together with low-grade changes in nerve conduction, suggest the possible influence of agents with a neurotoxic esterase-type activity independent of cholinesterase activity. Transient in-season neuropsychological changes in tests of mood status and performance were associated with exposure. Recommendations for exposure reduction include: accelerating the already declining use of pesticides in general, and organophosphates in particular; promoting the shift from more to less toxic organophosphates and other pesticides; and introducing rigid performance specifications for closed systems in loading and mixing at end-user sites. Dermal protection remains a problem. Cholinesterase activity levels and symptom interviews are useful for monitoring workers at risk, but alkyl phosphate levels are the definitive measure of exposure, surveys, investigations and surveillance.